Central Guesthouse at Thapae Gate is in the heart of the old town of Chiang Mai. It is easy to get around on foot, don't need any transportation to visit the temples and other historical sites.
There are many restaurants and bars around, also the pub street is only in a 5 minutes walk.
The Night Bazaar by the river is in 10 minutes walking distance and the most famous Sunday Walking Street is just on the corner. :)